For many centuries sails for wind propelled vehicles such as boats have been mounted upon a mast, usually with one or more booms supported upon the mast to maintain the sail in an extended position with respect to the mast. There are several factors that cause the historic ways of rigging sails upon a boat to provide very inefficient use of the available wind, and to produce an inherent tendency to capsize the vessel unless the sails are reefed in higher winds.
In the first place, the force of the wind upon a conventionally rigged sail tends to cause a boat to heel over, so that to achieve maximum speed it is necessary to operate at what are sometime dangerously tilted angles which fail to take maximum advantage of hull shape for efficient travel through the water. The tendency of a conventionally rigged sailboat to heel over makes it necessary to use a very heavy keel that adds substantially to the weight of the boat and to the underwater surface area that reduces the efficiency of the boat's progress through the water. In addition, the pressure of the wind upon the sail or sails tends to drive the hull of a conventionally rigged boat into the waves instead of lifting it over them.
Prior art patents known to applicant that disclose unconventional sail rigs for sailing vessels include Bailey U.S. Pat. No. 3,870,004, Smith 3,981,258, Smith et al. 4,228,750, and Denton 4,541,355; a PCT international patent application of Crowell et al published Apr. 24, 1986, Publication No. WO 86/02330; French Patent No. 1,156,952 of Maillett; and Dowler's British Patent No. 5342 of 1897.
None of the above-identified prior art is capable of producing the results that are possible with applicant's sail rig.
None of the above-listed prior art sail rigs possesses the safety features of the present device--i.e., they have neither the mounting of the sail and frame so that they are moved by wind pressure to a neutral position, nor the spring to move the sail and sail frame to a neutral position in a light wind. The French Patent to Maillett shows the use of springs, but they are for a totally different purpose and in no way suggests the use of a spring in the way that applicant uses it.
No prior art patent discloses any sail rig that is a simple, inexpensive and easy to mount and use as is applicant's.